Application of Conical Asperity in Contact Analysis of Rough Surfaces

A finite element analysis model with conical asperity is proposed to investigate the normal contact characters of rough surfaces in the micro perspective. The total normal elastic contact force acting on the single-cone contact region is obtained through definite integrate of the inverse hyperbolic cosine stress. A formula fitting the normal deformation of cone tip and the contact radius is given. Digital simulations show that although the inverse hyperbolic cosine stress has a natural logarithmic singular spot at the tip of the cone (at the center of the contact region), the total normal elastic contact force acting on the single-cone contact domain is bounded. The normal elastic contact load on single cone increases at first and then decreases with the increase of the half apex angle. The joint interface's total normal contact load increases with the decrease of the surface roughness. When the normal maximal deformation increases very evidently, the increase of the total normal contact load on joint interface is very small. The larger the half apex angle is, the larger the single-cone normal contact stiffness becomes. When the normal deformation of the cone tip increases, the single-cone normal contact stiffness slightly decreases at first and then keeps constant. When the normal critical deformation is smaller, the joint interface's total normal contact stiffness has an approximate linear increase with the increase of the normal critical deformation. The smaller the surface roughness is, the more evidently the joint interface's total normal contact stiffness increases. When the normal critical deformation is larger, the joint interface's whole normal contact stiffness approaches constant. © 2017, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.